From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.net ([212.227.17.20]:59481 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751639AbaLFUTX (ORCPT ); Sat, 6 Dec 2014 15:19:23 -0500 Message-ID: <548364C2.10401@gmx.de> Date: Sat, 06 Dec 2014 21:19:14 +0100 From: Hartmut Knaack MIME-Version: 1.0 To: Vlad Dogaru , linux-iio@vger.kernel.org Subject: Re: [PATCH 2/4] iio: ensure scan index is unique at buffer register References: <1416919687-14271-1-git-send-email-vlad.dogaru@intel.com> <1416919687-14271-3-git-send-email-vlad.dogaru@intel.com> In-Reply-To: <1416919687-14271-3-git-send-email-vlad.dogaru@intel.com> Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-iio-owner@vger.kernel.org List-Id: linux-iio@vger.kernel.org Vlad Dogaru wrote on 25.11.2014 13:48: > Having two or more channels with the same positive scan_index field > makes no sense. Prevent this situation by failing to register a buffer > if two scan indexes are identical. > > Signed-off-by: Vlad Dogaru > --- > drivers/iio/industrialio-buffer.c | 28 ++++++++++++++++++++++++++++ > 1 file changed, 28 insertions(+) > > diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c > index f971f79..422b29e 100644 > --- a/drivers/iio/industrialio-buffer.c > +++ b/drivers/iio/industrialio-buffer.c > @@ -309,6 +309,30 @@ static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev, > return ret; > } > > +static int iio_check_unique_scan_index(struct iio_dev *indio_dev, > + const struct iio_chan_spec *channels, > + int num_channels) > +{ > + int i, j; > + > + for (i = 0; i < num_channels - 1; i++) { > + if (channels[i].scan_index < 0) > + continue; > + for (j = i + 1; j < num_channels; j++) { > + if (channels[j].scan_index < 0) > + continue; This check up here is unnecessary, since channels[i].scan_index is already equal or greater zero, so the check below results in a false for channels[j].scan_index smaller than zero and cause a new loop iteration anyway. > + if (channels[i].scan_index == channels[j].scan_index) { > + dev_err(&indio_dev->dev, > + "duplicate scan index %d\n", > + channels[i].scan_index); > + return -EINVAL; > + } > + } > + } > + > + return 0; > +} > + > static const char * const iio_scan_elements_group_name = "scan_elements"; > > int iio_buffer_register(struct iio_dev *indio_dev, > @@ -320,6 +344,10 @@ int iio_buffer_register(struct iio_dev *indio_dev, > struct iio_buffer *buffer = indio_dev->buffer; > int ret, i, attrn, attrcount, attrcount_orig = 0; > > + ret = iio_check_unique_scan_index(indio_dev, channels, num_channels); > + if (ret < 0) > + return ret; > + > if (buffer->attrs) > indio_dev->groups[indio_dev->groupcounter++] = buffer->attrs; > >